On Thursday evening, Victoria Police Chief Commissioner Graham Ashton said the freeway's cameras and bodycam footage from the officers contains "quite illustrative" evidence of what happened.
"We've got a lot of evidence to piece together and while we currently don't know [what caused the crash], we will know before too much longer," he told A Current Affair.
Pusey has left hundreds of TripAdvisor reviews, including ones where he boasted about "racing" his Porsche.
"When I'm not racing my Porsche or chasing the Sky Bus for its free Wi-Fi I like to get up and dance," Pusey wrote on a November 2018 review of a Melbourne helicopter company.
"I've found these folks are particularly good at such things and will return one day when my heads not already near the clouds."
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A month earlier, Pusey reviewed Melbourne Airport's SkyBus company.
"I like to drive behind the bus in my Porsche because it doesn't have Wi-Fi," he wrote.
"I set the cruise control so as to allow me to social network and all that cool new age type stuff that's all the rage. Me and my Porsche enjoy the day out doing this activity."
Pusey's Porsche, which is registered in Queensland, was also seen in recent dashcam footage speeding down the same freeway a month ago.
There is no suggestion Pusey was driving, however it is the same car.
In the footage, the driver, travelling at 100km/h, can be heard saying "what a f**king idiot" when the Porsche flies past him.
Police have not yet spoken to the driver of the semi-trailer which crashed into the scene. Mohinder Singh Bajwa remains in hospital and is yet to be interviewed.
Victoria Police has urged people to honour the four officers killed by tying a blue ribbon outside their home.
Leading Senior Constable Lynette Taylor, Constable Glen Humphris, Senior Constable Kevin King and Constable Josh Prestney have been identified as the officers who died in the tragedy.
On Thursday night, Melbourne's most famous landmarks were bathed in blue light to mark their deaths. An in memoriam page set up by Victoria Police was flooded with tributes.
"To honour them, we're asking Victorians to turn the state blue. Tie a blue ribbon outside your home. It could be to the front door or gate, wherever it can be seen," the police force said on Twitter.
"It's a small gesture to show your support for the men & women who keep our communities safe every day."
Detectives are still investigating the tragic crash that led to the single biggest loss of lives in state history.
Commissioner Ashton said the semi trailer driven by Bajwa "appears to have moved from one of the traffic lanes of the freeway into the emergency lane and travelled a short distance in the emergency lane at around 100km/h".
He said Bajwa suffered a "medical episode", "which seemed to involve him blacking out".
"The investigation into the exact cause of the collision remains ongoing," the force said in a statement.
"Anyone who witnessed the incident or with information is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential report online at www.crimestoppersvic.com.au."
